1. Field of the Invention
This invention relates to an electronic musical instrument which generates parameters specifying a musical tone wave form and controlling a musical tone wave form generation with the aid of a neural network.
2. Description of the Prior Art
The parameters to control the musical tone in the electronic musical instrument are a wave form data which specifies the wave form of the musical tone, an envelope data which specifies an output level of the musical tone wave form, a pitch data which specifies a tone pitch, etc. Several musical tone parameters are stored in a memory of the electronic musical instrument, and can be freely read by a player to play, varying expression. A part of the musical tone parameters is previously stored in the memory of the musical instrument before shipping thereof, and remaining another part of the musical tone parameters can be stored in the memory before the player plays the instrument.
The musical tone parameters stored in the memory in advance can be freely selected for playing by the player while playing the instrument. However, the parameters not stored in the memory cannot be selected. It takes too much time to set new parameters while the player plays the musical instrument, so that this setting was impractical. As a result of this the parameter selection range is too narrow, and play expression is poor.
If more musical tone parameters are stored in the memory for widening the selection range, larger memory is required and it takes much time to store the parameters.
The FM (Frequency Modulation) tone source is one of the conventionally applied tone sources to the electronic musical instrument. The FM tone source synthesize a musical tone by combining (modulating and adding) four or six operators each of which can be set basic wave form (sine wave, triangle wave, etc.), frequency (tone pitch), out put level, envelope, etc. based on a specific algorithm. This tone source can generate beautiful and varied musical tones with simple configuration.
However, it has been regarded that it is difficult to generate the musical tone using the FM tone source according to player's intention. This is mainly due to that it is difficult to predict the change of the musical tone based on the change of the operator and the algorithm since the musical tone is generated by using many parameters and FM modulation.
An example is an electronic musical instrument which is designed to set the pitch of the musical tone to be generated according to ON/OFF pattern of several play keys such as electronic musical wind instrument. Generally, such an electronic musical instrument is provided with a table which stores the pitch data corresponding to several ON/OFF patterns. This table is retrieved according to the ON/OFF pattern by player's operation to find the specific pitch.
In such electronic musical instrument, the ON/OFF pattern of the playing keys can set only the pitch, but the tone color (wave form) of the musical tone was constant irrespective of pitch. In case of natural musical instrument the tone color (wave form) varies delicately depending on the pitch even when the musical instrument (tone color) is the same, and this delicate change of the tone color affects significantly expression of the musical instrument. Moreover, even when the pitch is constant, the tone color changes if fingering pattern is changed. So as to change the tone color as discussed above on the electronic musical instrument, generally, it is necessary to sample the wave form of natural musical instrument for each ON/OFF pattern of the keys and for each pitch and to read out a wave form data. However, these wave form data for each pitch need a large memory capacity to store them, due to which the size of the musical instrument is increased, and its cost rises.